Using a double pumper carburetor from Holley or Holley style carburetor will need some requirements vs a vacuum secondary Holley in order for it to operate correctly on the secondary side opening. A double pumper needs quick rpms and a vehicle that is light and not something heavy that takes a bit to get going as a double pumper when hitting the throttle and you end up opening up the secondary side of things, without quick enough rpms to get the vehicle moving it will be a big bog and a real soggy signal catching up with the load on the engine.
They can work with vehicles that can get rpms up quickly in the rpm band of its said build and camshaft rpm range and also if setup correctly. It can be used on automatic transmissions and does not need some high 3000 plus stall convertor like Holley recommends as I have used them many times on a th350 using just a 2200 stall convertor and 3.42 rear gearing. The success is my truck could hit the rpms very quickly and pick up speed without any lugging.
A vacuum secondary Holley like mentioned would be the better choice as it can be made to open up to demand as it goes by air velocity as does a Qjet carburetor. The Quick fuel brawler 750 carbs would be a good investment if you want to go that route and they have an adjustable vacuum secondary pod that you can control the rate it opens up. With a double pumper if its not sized or tuned correctly its not very forgiving. With you having a big block a 750 would be more then enough for it but the style depends on the setup such as your rear gearing and the vehicle weight and how quick it gets up to speed and other factors.
You don't want to end up with a band aid tune on the double pumper with a 50cc secondary pump shot size to cure a massive bog because its not the best choice for your vehicle. I have seen many times folks can't get one properly tuned because its not the right carb choice for there ride and end up with band aid type of a tune such as a big 50cc pump shot on either the front and rear both on the pump shot circuit. A Qjet will give better mileage and overall better results as far as being the best fuel metering but a Holley will give more performance if a more performance oriented build.
They can work with vehicles that can get rpms up quickly in the rpm band of its said build and camshaft rpm range and also if setup correctly. It can be used on automatic transmissions and does not need some high 3000 plus stall convertor like Holley recommends as I have used them many times on a th350 using just a 2200 stall convertor and 3.42 rear gearing. The success is my truck could hit the rpms very quickly and pick up speed without any lugging.
A vacuum secondary Holley like mentioned would be the better choice as it can be made to open up to demand as it goes by air velocity as does a Qjet carburetor. The Quick fuel brawler 750 carbs would be a good investment if you want to go that route and they have an adjustable vacuum secondary pod that you can control the rate it opens up. With a double pumper if its not sized or tuned correctly its not very forgiving. With you having a big block a 750 would be more then enough for it but the style depends on the setup such as your rear gearing and the vehicle weight and how quick it gets up to speed and other factors.
You don't want to end up with a band aid tune on the double pumper with a 50cc secondary pump shot size to cure a massive bog because its not the best choice for your vehicle. I have seen many times folks can't get one properly tuned because its not the right carb choice for there ride and end up with band aid type of a tune such as a big 50cc pump shot on either the front and rear both on the pump shot circuit. A Qjet will give better mileage and overall better results as far as being the best fuel metering but a Holley will give more performance if a more performance oriented build.
